Plasma weapons do both electrical and fire damage. In the core rule book they are the only weapons that deal two types of damage. Both the Shock and Flaming fusions refer to placing that fusion on a weapon with two types of damage, but also note the fusion can't be placed on a weapon that already deals that type of damage.
It seems obvious there would be no point in placing such a fusion on a weapon that already did only that type of energy damage. However there would be a possible benefit in enabling a plasma weapon to produce all fire or all electrical damage by using such a fusion.
Is the reference in the Shock and Flaming fusion description to weapons with two types of damage irrelevant given there is only one type of weapon (plasma) that does such?
Or should the energy fusion text clarify that they can't be placed on weapons that only deal that type of damage (single, not plural)?
Note Herolab Online will not allow a Shock Fusion to be added to a plasma weapon, but it will allow a Shock Fusion Seal to be added to a plasma weapon at which point you can set the fusion to override the fire type of damage.
I'm guessing the energy fusion text just got copied from one version to another and perhaps the situation above was not considered. Though I am curious as to what the point of forbidding placing the fusion on a weapon that deals the same energy type is? That seems pointless, except in the case of plasma weapons.
Is Herolab Online in error or does the energy fusion text just need some clarification?